Xsession fail to start on ubuntu focal/eoan

[r3vn]

xsession setup
setup process seems to work fine using debian.sh

xsession start
Xwayland immediately crash after connecting to qxdisplay's socket

start_desktop.sh output on ubuntu eoan:

root@ubu-xfce:/# /mnt/guest/start_desktop.sh 5 user

glamor: 'wl_drm' not supported
Missing Wayland requirements for glamor GBM backend
Failed to initialize glamor, falling back to sw
xinit: XFree86_VT property unexpectedly has 0 items instead of 1
The XKEYBOARD keymap compiler (xkbcomp) reports:
> Warning:          Unsupported maximum keycode 774, clipping.
>                   X11 cannot support keycodes above 255.
Errors from xkbcomp are not fatal to the X server
xinit: connection to X server lost

waiting for X server to shut down ....
......
xinit: X server slow to shut down, sending KILL signal

waiting for server to die